clk: msm: clock: Return error to clients if branch clock enable times out

Currently, when enabling a branch clock times out, the clock
driver prints out a warning but does not return an error to
the caller of the function. This leads to clients assuming
that the clock turned on correctly and them taking next steps
with that erroneous assumption. This sometimes leads to fatal
failures whose cause might not be obvious.
Return an error code to let clients do the necessary cleanup
at their end in the instance that turning on a branch clock
fails.

CRs-Fixed: 1055889
Change-Id: Ibe8221ce0faa1d59405187a71c4527d5d8387790
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>